This NEMA-17 motor has an integrated Planetary gearbox with a 52/11 :1 ratio. It comes with the rear shaft exposed, so you can mount an encoder or shaft coupler. When connected to a 1067 - PhidgetStepper Bipolar HC, the 3325 has a maximum speed of approximately 900 RPM. At the output of the gearbox, the step angle is a little under 0.35°. When using the step angle in calculations, you should derive the exact step angle by dividing 1.8° by the gearbox reduction ratio. At 1.7 Amps, this stepper motor can produce a maximum torque of 18.6 kg-cm. However, the gearbox is only rated for 18 kg-cm of continuous torque. Loading this gearbox stepper beyond the torque rating of the gearbox will shorten its useful life. Motor Controller and Connection The 3325 stepper motor connects to a bipolar motor controller such as the 1067 - PhidgetStepper Bipolar HC. The following diagram shows how to connect the motor wires to the board connectors to produce a clockwise rotation in the stepper motor when increasing position. To wire for counter-clockwise rotation when increasing position, reverse the red and blue wires. Note: Make sure to unplug the power cord from the motor controller before switching wires around. The rear shaft of this motor can be equipped with the HKT22 Optical Encoder for applications where you need to keep track of the exact position, velocity, or acceleration of the motor.Phidget